that's a big claim. >> that's right. it's a claim that has been ignored by historians traditionally, they never sort of want to touch the personal lives of the presidents. >> john: tawdry. >> presidential, they missed a major component of the story of america, that is that the private lives of the presidents and first ladies did shape how things went. for example the civil war. >> john: you say that james buchanan's gay love affair helped cause the civil war. >> that's right part of the story. james buchanan arrives in washington, a young congressman from lancaster, pennsylvania. a heavy abolitionist portion of the country. >> john: he wants to abolish slavery. >> he's there, politically ambitious and comes under the wing and tutelage of senator refuse king, a slave owner from alabama and two of them fall in love and they have a 32 year long love affair. >> john: how do you know they have a love affair. >> well-known in washington d.c., people were talking about it. they were known at the time as siamese twins, they were